A. Field of the Invention
The embodiments of the present invention relate to a backup power source, and more particularly, the embodiments of the present invention relate to a capacitive-based system for providing an electrical backup power source for an electric actuator for fiil-safe actuation.
B. Description of the Prior Art
(a) Electric Actuators.
Electric actuators are used in many industries including refining, process, water, waste-water, HVAC, and more. Electric actuators are used to electromechanically operate valves, dampers, gear boxes, and other apparatus to predetermined positions.
With a loss of primary power to an electric actuator, operating the apparatus to a fail-safe position is not possible without a backup power source. Conventional backup power sources for electric actuators include battery-based electrical backup power systems, hydraulic or pneumatic backup power systems, and mechanical backup power systems utilizing springs.
(b) Battery-based Electrical Backup Power Systems.
Battery-based electrical backup power systems are problematic due to their weight, complex maintenance, limited temperature range, and hazardous materials inherent to batteries and the disposal thereof.
(c) Hydraulic or Pneumatic Backup Power Systems.
Hydraulic or pneumatic backup power systems must be attached to the electric actuator, are physically large and heavy, have a restrictive temperature range, and in the case of pneumatics have a restrictive power range.
(d) Mechanical Backup Power Systems.
Mechanical backup power systems consisting of wound springs must be attached to the actuator, have limited torque, require larger actuators to tighten the spring, and have a limited operational range.